<template>
  <div ref="wrapper">
    <router-link
      v-show="showHeader"
      tag="div"
      to="/"
      class="header-abs">
      <i class="el-icon-arrow-left header-abs-back"></i>
    </router-link>
    <div
      :style="opacityStyle"
      v-show="!showHeader"
      class="header-fixed"
    >
      <router-link
        tag="div"
        to="/"
        class="header-fixed-back">
        <i class="el-icon-arrow-left "></i>
      </router-link>
      景点详情
    </div>
  </div>
</template>

<script>
export default {
  data: function () {
    return {
      showHeader: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll: function () {
      var top = document.documentElement.scrollTop
      console.log(top)
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showHeader = false
      } else {
        this.showHeader = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
  @import "../../assets/varibles.styl"
  .header-abs
    position: absolute
    left: .2rem
    top: .2rem
    width: .8rem
    height: .8rem
    line-height: .9rem
    border-radius: .4rem
    text-align: center
    background: rgba(0, 0, 0, .8)

    .header-abs-back
      color: #fff
      font-size: .4rem

  .header-fixed
    z-index: 2
    position: fixed
    top: 0
    left: 0
    right: 0
    height: $headerHeight
    line-height: $headerHeight
    text-align: center
    color: #fff
    background: $bgColor
    font-size: .32rem

    .header-fixed-back
      position: absolute
      top: 0
      left: .2rem
      width: .64rem
      text-align: center
      font-size: .4rem
      color: #fff
</style>
